Brightening of a dark monolayer semiconductor via strong light-matter coupling in a cavity

Hangyong Shan, Ivan Iorsh, Bo Han, Christoph Rupprecht, Heiko Knopf, Falk Eilenberger, Martin Esmann, Kentaro Yumigeta, Kenji Watanabe, Takashi Taniguchi, Sebastian Klembt, Sven Höfling, Sefaattin Tongay, Carlos Antón-Solanas, Ivan A. Shelykh, Christian Schneider*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Engineering the properties of quantum materials via strong light-matter coupling is a compelling research direction with a multiplicity of modern applications. Those range from modifying charge transport in organic molecules, steering particle correlation and interactions, and even controlling chemical reactions. Here, we study the modification of the material properties via strong coupling and demonstrate an effective inversion of the excitonic band-ordering in a monolayer of WSe2 with spin-forbidden, optically dark ground state. In our experiments, we harness the strong light-matter coupling between cavity photon and the high energy, spin-allowed bright exciton, and thus creating two bright polaritonic modes in the optical bandgap with the lower polariton mode pushed below the WSe2 dark state. We demonstrate that in this regime the commonly observed luminescence quenching stemming from the fast relaxation to the dark ground state is prevented, which results in the brightening of this intrinsically dark material. We probe this effective brightening by temperature-dependent photoluminescence, and we find an excellent agreement with a theoretical model accounting for the inversion of the band ordering and phonon-assisted polariton relaxation.

Original languageEnglish
Article number3001
Pages (from-to)3001
JournalNature Communications
Volume13
Issue number1
DOIs
Publication statusPublished - 30 May 2022

Bibliographical note

Funding Information:
The authors gratefully acknowledge funding by the State of Lower Saxony. Funding provided by the European Research Council (ERC project 679288, unlimit-2D) is acknowledged. C.S. and B.H. acknowledge financial support by The German Research Foundation (DFG) (SCHN1376/14-1, SPP 2244). S.H. acknowledges financial support by the DFG (HO 5194/16-1) and INST 93/932-1 FUGG. H.S. acknowledges the Sino-Germany (CSC-DAAD) Postdoctoral Scholarship Program from China Scholarship Council and German Academic Exchange Service. I.I. and I.A.S. acknowledge the support from the joint RFBR-DFG project No. 21-52-12038. I.I. acknowledges the support Ministry of Science and Higher Education of Russian Federation, goszadanie no. 2019-1246. S.T acknowledges support from DOE-SC0020653 (materials synthesis), Applied Materials Inc., NSF CMMI 1825594 (NMR and TEM studies), NSF DMR-1955889 (magnetic measurements), NSF CMMI-1933214, NSF 1904716, NSF 1935994, NSF ECCS 2052527, DMR 2111812, and CMMI 2129412. K.W. and T.T. acknowledge support from the Elemental Strategy Initiative conducted by the MEXT, Japan (Grant Number JPMXP0112101001) and JSPS KAKENHI (Grant Numbers JP19H05790 and JP20H00354). M.E. acknowledges funding by the University of Oldenburg through a Carl-von-Ossietzky fellowship. F.E. and H.K. are supported by the Federal Ministry of Education and Science of Germany under Grant ID 13XP5053A.

Funding Information:
The authors gratefully acknowledge funding by the State of Lower Saxony. Funding provided by the European Research Council (ERC project 679288, unlimit-2D) is acknowledged. C.S. and B.H. acknowledge financial support by The German Research Foundation (DFG) (SCHN1376/14-1, SPP 2244). S.H. acknowledges financial support by the DFG (HO 5194/16-1) and INST 93/932-1 FUGG. H.S. acknowledges the Sino-Germany (CSC-DAAD) Postdoctoral Scholarship Program from China Scholarship Council and German Academic Exchange Service. I.I. and I.A.S. acknowledge the support from the joint RFBR-DFG project No. 21-52-12038. I.I. acknowledges the support Ministry of Science and Higher Education of Russian Federation, goszadanie no. 2019-1246. S.T acknowledges support from DOE-SC0020653 (materials synthesis), Applied Materials Inc., NSF CMMI 1825594 (NMR and TEM studies), NSF DMR-1955889 (magnetic measurements), NSF CMMI-1933214, NSF 1904716, NSF 1935994, NSF ECCS 2052527, DMR 2111812, and CMMI 2129412. K.W. and T.T. acknowledge support from the Elemental Strategy Initiative conducted by the MEXT, Japan (Grant Number JPMXP0112101001) and JSPS KAKENHI (Grant Numbers JP19H05790 and JP20H00354). M.E. acknowledges funding by the University of Oldenburg through a Carl-von-Ossietzky fellowship. F.E. and H.K. are supported by the Federal Ministry of Education and Science of Germany under Grant ID 13XP5053A.

Publisher Copyright:
© 2022, The Author(s).

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